Inter-annual Variability Of Water Mass Distribution Percent In The Source Area Of The Yellow Sea Warm Current

The Source Area of the Yellow Sea Warm Current is located in the southwest of Cheju Island, across Yellow and East China Seas, adjacent to the sea of Japan, over the continental shelf. It is influenced by Kuroshio, the Tsushima Warm Current, Taiwan warm current, the Yellow Sea coastal current, the Changjiang River diluted water and the Yellow Sea cold water mass, that is, it is the region of interaction of multiple water masses. Water mass analysis has an important role in not only marine fisheries, but also development in marine resources, marine pollution, and even national defense construction.What’s more, understanding inter-annual variation characteristics of water mass helps to further study large scale ocean thermal conditions and the dynamic conditions and the interaction of air-sea.Nucleus for European Modeling of the Ocean (NEMO) in the Pacific Northwest uses the "two-way nested" technology to improve the simulation, its horizontal resolution can reach 1/4 degrees. Base on simulation result of temperature salinity and current velocity from 1958 to 2007,and the multi concentration mixing proportion scheme, the research is performed to obtain water mass composition, the boundaries of water masses and the volume percent of each water mass in winter and summer from 1958 to 2007.the main conclusions are as follows:There is seasonal variation of the number of water mass in the Source Area of the Yellow Sea Warm Current. There are 2 water in winter, the bottom of the table is consistent, East and west sides are the Kuroshio water of the East China Sea(KE) and Shelf mixed water of the East China Sea (EM),volume percent being 74%,26%, respectively, the former is obviously higher than the latter. In summer there are 3 water, the bottom of the table are respectively occupied by different water masses, East and west sides of the surface layer are Kuroshio surface water(KES)and Surface water of the East China Sea(ES), respectively; the Kuroshio subsurface water covering the bottom, gradually degeneration from deep to shallow, their volume percent being 35%,8%,54% respectively. Although the number of water mass in the Source Area of the Yellow Sea Warm Current exists seasonal change, there exists no inter-annual variability of the number of water masses in winter and summer, with the inter-annual variability of the range of water masses in the study area.By annual volume percent, among the year from 1958 to 2007,nine years are defined to be typically strong KE years while another nine years are typically weak KE years, the others are normal. Since KE and EM in the study area is the shift in the relationship, so the years of KE being strong that of EM being weak, and vice versa. The inter-annual variation in the distribution of the two water masses is controlled by the Yellow Sea Warm Current, the Yellow Sea coastal current, Taiwan warm current.Among the year from 1958 to 2007, six years are strong ES years while another seven years are weak, the others are normal. ES is mainly influenced by the Changjiang diluted water, vertical thickness is small. The inter-annual variability of its volume is correlated with that of KES, the correlation coefficient is -0.45, but not correlated with that of KEB.Among the year from 1958 to 2007, ten years are strong KES years while another seven years are weak; the others are normal. Seven years are strong KEB years while nine years are weak, the rest is normal. KE Sand KEB in the study area accords basically with the shift in the relationship, their correlation coefficient is -0.88, so the years of KEB being strong that of KES being weak, on the other hand, is also established basically. KEB is dominant in the bottom layer, what’s more, the bottom is influenced by the intrusion of the Yellow Sea cold water mass and the Yellow Sea coastal current with high temperature.